SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fa5b6b54ba8d4d14a3dc187394b0c62c1756b667c0aeb1995cef88975de9a0b' 
  AND token = 'E9uRIjG3/ixdkRWJMwBbXH5UhnGJVGZjksGNwxPPyYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}